Fenton法和类Fenton法降解土壤中的二苯砷酸

本文对Fenton法与类Fenton法降解土壤中的二苯砷酸(diphenylarsinic acid,DPAA)进行了研究.考察了H2O2投加量和催化剂种类(Fe2+/Fe3+)对红壤及黑土中DPAA降解效果的影响,并采用高效液相色谱-质谱联用法(HPLC-MS/MS)对降解中间产物进行了初步鉴定.结果显示,针对红壤与黑土分别采用类Fenton法与Fenton法,在H2O2投加浓度为1 mol·L-1,含铁催化剂浓度为0.25 mol·L-1,土水比为1∶3,反应时间为1h的条件下,红壤及黑土中DPAA的降解率均可达到65%以上.HPLC-MS/MS的分析结果表明,DPAA可脱苯环形成降解产物苯砷酸(phenylarsinic acid,PAA),而PAA进一步氧化生成无机砷,这可能是Fenton/类Fenton法降解DPAA的途径之一.     

多年连续种植转基因Bt汕优63稻田水体和土壤中Cry1Ab/c蛋白残留调查

以湖北武汉、随州、武穴和孝感以及山东德州5个多年转基因水稻种植区为试验地,在水稻生育期采集转cry1 Ab/c基因水稻Bt汕优63(Bt-SY63)和对照非转基因汕优63(SY63)稻田水体和土壤,使用酶联免疫吸附测定(ELISA)方法对稻田水体和土壤Cry1 Ab/c蛋白残留量进行动态监测.结果显示,与SY63稻田相比,连续种植2～4 a后,不同生育期Bt-SY63稻田水体Cry1Ab/c蛋白残留量大多与同一生育期SY63样品间差异未达显著水平(P＞0.05),最高残留量为0.373 ng· mL-1.与水体Cry1Ab/c蛋白残留情况相似,不同生育期Bt-SY63稻田土壤Cry 1Ab/c蛋白残留量大都低于试剂盒检测限(0.25 ng·g-1),仅随州苗期、德州拔节期和开花期样品有微量残留,鲜土残留量分别为0.261、0.540和0.361 ng·g-1,并分别与SY63样品间差异显著(P＜0.05).另外,多年连续种植Bt-SY63水稻后,2、3和4a种植年限的Bt-SY63稻田水体和土壤中Cry1Ab/c蛋白残留量之间大都没有显著差异(P＞0.05).认为连续种植2、3和4a的Bt-SY63水稻稻田水体和土壤仅存在微量Cry1Ab/c蛋白残留,不会造成Cry1Ab/c蛋白在稻田水体和土壤中的累积.     

Effects of soil nematodes communities on litter decomposition in urban forest of Dalian北大核心CSCD

In order to further expound the effect of soil nematodes on litter decomposition in urban forest, this study investigated the responses of soil nematodes communities to litter decomposition by litterbags technology at different mesh sizes in Dalian National Forest Park. Soil nematodes community composition, decomposition rate of litter and nutrient release were also analyzed. It found a total of 4 418 nematodes from 39 genera. Higher relative density of soil nematodes was found in the bags with 0.1 mm mesh size (1.55 individuals and 7.34 orders per g of dry litter) compared to the bags with 0.02 mm mesh size (0.21 individuals and 0.49 orders per g of dry litter). There were very few soil nematodes in the 0.02 mm litter bags. Thus we regarded that soil nematodes only affected the 0.1 mm litter bags. The mass loss rates as well as C and P release rates was higher in litter bags with 0.1 mm mesh size than in those with 0.02 mm mesh size, indicating a significant influence of soil nematodes on mass loss and nutrient release. The contribution of soil nematodes to the litter mass loss was about 24%. The effect of soil nematodes on the nutrient release rates differed among elements. The soil nematodes had a bigger influence on the release rate of N than that of other elements, whereas the influence on K release rate was the lowest. The results showed that soil nematodes communities has a significant effect on the litter decomposition and nutrient release of the forest litter in Dalian city, especially promoting the mass loss rates and N release rates.     

Soil and water loss in the Lancang River-Mekong River watershed (in Yunnan section, China) and its control measures

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垃圾填埋场室内模拟试验注水量确定方法及其应用

针对填埋场室内模拟试验往往忽略降雨径流和初损的问题,提出运用SCS模型确定室内模拟试验日注水量的方法,并将计算结果应用于成都长安填埋场室内模拟试验中.结果表明,采用SCS模型计算所得的日入渗量进行注水的模拟柱渗滤液产量和水质变化能够更准确的模拟填埋场实际情况.     

Mitigation and remediation technologies for organic contaminated soils

Organic contaminated soils have become a widespread environmental problem, which may lead to a great threat to the quality of agricultural production and to human health. Physical, chemical, and biological technologies have been employed for the mitigation and remediation of organic contaminated soils. This paper reviews the progress of mitigation and remediation technologies for organic contaminated soils and suggests two different strategies for the mitigation of ’slightly-contaminated’ agricultural soils and the remediation of ‘heavily-contaminated’ soils/sites, respectively. On this basis, directions for future research in this field are suggested.     

Removal of high concentrations of polycyclic aromatic hydrocarbons from contaminated soil by biodiesel

Solubilizing experiments were carried out to evaluate the ability of biodiesel to remove polycyclic aromatic hydrocarbons (PAHs) from highly contaminated manufactured gas plant (MGP) and PAHs spiked soils with hydroxypropyl-β-cyclodextrin (HPCD) and tween 80 as comparisons. Biodiesel displayed the highest solubilities of phenanthrene (420.7 mg·L^-1), pyrene (541.0 mg·L^-1), and benzo(a)pyrene (436.3 mg·L^-1). These corresponded to several fold increases relative to 10% HPCD and tween 80. Biodiesel showed a good efficiency for PAH removal from the spiked and MGP soils for both low molecular weight and high molecular weight PAHs at high concentrations. Biodiesel was the best agent for PAH removal from the spiked soils as compared with HPCD and tween 80; as over 77.9% of individual PAH were removed by biodiesel. Tween 80 also showed comparable capability with biodiesel for PAH solubilization at a concentration of 10% for the spiked soils. Biodiesel solubilized a wider range of PAHs as compared to HPCD and tween 80 for the MPG soils. At PAH concentrations of 229.6 and 996.9 mg·kg^-1, biodiesel showed obvious advantage over the 10% HPCD and tween 80, because it removed higher than 80% of total PAH. In this study, a significant difference between PAH removals from the spiked and field MGP soils was observed; PAH removals from the MGP soil by HPCD and tween 80 were much lower than those from the spiked soil. These results demonstrate that the potential for utilizing biodiesel for remediation of highly PAH-contaminated soil has been established.     

非离子表面活性剂淋洗萘污染土壤的修复研究

采用土柱实验研究了非离子表面活性剂对焦化厂萘污染砂土的淋洗效果,同时研究了超声预处理对非离子表面活性剂土壤淋洗的增强效果及粉土和粘土对非离子表面活性剂土壤淋洗的不利影响.研究表明,1)1g·L-1的TritonX-100、AEO-9和Tween80对同一萘浓度(192.4mg·kg-1)的土壤洗脱效率分别为73.0%、81.5%和59.0%,2g·L-1的表面活性剂的洗脱效率要高于1g·L-1的洗脱率,分别为96.5%、95.1%和88.2%.2)对土壤进行短时超声处理(80Hz)促进了洗脱率的提高,超声10min的淋洗效果要高于超声5min的淋洗效果;土壤分别经5min和10min超声处理后,2g·L-1浓度的TritonX-100对萘的洗脱率从94%分别提高到98.8%和99.6%,洗脱时间从255min分别减少到172min和160min.3)砂土中含有粉土和粘土对洗脱效果有不利影响,且粘土的影响要更严重,当萘污染的砂土混入5%的粘土时,2g·L-1浓度的TritonX-100对萘的洗脱率从94.7%下降至73.8%,洗脱时间从255min增加至605min,而混入20%的粉土洗脱率仅下降到88.4%,洗脱时间增加至512min.     

不同土地利用方式下Cd、Pb复合污染对土壤酶活性的影响

为探寻合理的土地利用方式,减轻重金属污染,以上海市崇明岛为研究对象,结合室内盆栽模拟试验,研究了不同土地利用方式下Cd、Pb复合污染对土壤酶活性的影响,以期为合理规划土地功能和提高土壤健康程度提供科学依据。试验结果表明,农田、生活用地等受人类活动影响较明显的地区,其土壤酶活性低于湿地、林地、河道旁等人为扰动较少且水分充足的地区;土壤脲酶、磷酸酶和脱氢酶活性两两之间呈显著正相关(P<0.01),且土壤脲酶对Cd、Pb较敏感;土壤有机质与土壤酶活性呈显著正相关(P<0.05);Cd、Pb复合污染在低含量(Cd:0～1mg.kg-1;Pb:0～60mg.kg-1)时对土壤酶活性表现为促进作用,而高含量(Cd:0～20mg.kg-1;Pb:0～100mg.kg-1)时则表现为抑制作用。     

噻吩磺隆在棕壤中的降解特性

采用实验室模拟试验研究了微生物及不同环境条件对土壤中噻吩磺隆降解的影响。结果表明,噻吩磺隆降解速率与土壤温度、湿度呈正相关,与农药初始用量呈负相关,噻吩磺隆在土壤中的降解以微生物降解为主。当温度从5上升到35℃时,噻吩磺隆的降解速率增加了2.9倍;当土壤湿度从饱和含水量的25%提高到75%时,噻吩磺隆的降解半衰期由7.6缩短至2.6d;当土壤中噻吩磺隆初始用量从2.5增加到10.0mg.kg-1时,其降解半衰期由3.1延长至7.6d;未灭菌土壤中噻吩磺隆降解迅速,半衰期为3.9d,而灭菌土壤中噻吩磺隆降解半衰期延长至14.7d。